The invention relates to a rotating magnetron cathode and to a method for the use of a rotating magnetron cathode with a substantially hollow cylindrical target and a magnet system which is provided in the cavity formed by the target, for the formation of a plasma for coating planar substrates which can be moved past the cathode, by means of a cathode sputtering process.
An apparatus and method are known (U.S. Pat. No. 4,356,073) which are suitable for sputtering thin coatings on substantially planar substrates, having an evacuable chamber, a cathode including a tubular cylindrical component containing the coating material to be sputtered, magnets, means for rotating the tubular component, and means for holding and transporting the substrates in the chamber.
In the sputtering of reactive material, before the actual coating process begins, first the undesired coating on the surface of the target to be sputtered is removed. This is performed, as is generally known, by strip-sputtering wherein the material thus sputtered is applied to a plate which is provided approximately in the plane of the substrate that is to be coated. Not until the undesired coating--an oxide coating for example--is removed is the substrate brought into the coating zone and the coating process begun.
In the case of highly reactive materials there are the disadvantages that, through a permanent reaction, such as the oxidation of the target material, no satisfactory sputtering rate can be achieved, and that the sputtering process is disturbed or interrupted by arcs forming on the target surface.